[Radiance-general] Alpha Channel - Z-Buffer Images

[Kirk Thibault]

Hi folks - I apologize if this is covered in the Rendering with 
Radiance text, I am awaiting the Book Surge printing of it as we speak. 
  Does Radiance store and/or recover the alpha channel or z-buffer 
information for a scene and, if so, can either be output to an image 
for compositing and Depth of Field effects in another app like 
Photoshop?

Thanks,

Kirk